Fluorescence Detection of Pleural Malignancies Using 5-Aminolaevulinic Acid

Autofluorescence imaging-assisted medical thoracoscopy in the diagnosis of malignant pleural disease

BACKGROUND

Medical thoracoscopy (MT) does not always provide a conclusive diagnosis of pleural diseases because the endoscopic appearance of pleural diseases can be misleading. Autofluorescence imaging (AFI) is an effective assistive diagnostic tool. However, its clinical application for pleural disease remains controversial.

OBJECTIVES

This prospective study evaluated the clinical usefulness of AFI-assisted MT for diagnosis of malignant pleural diseases.

METHODS

Patients with unexplained pleural effusion admitted to our clinics between December 2018 and September 2021 were enrolled. We performed white-light thoracoscopy (WLT) first, and then AFI, during MT. Images of endoscopic real-time lesions were recorded under both modes. Pleural biopsy specimens were analyzed pathologically. Between-groups differences in diagnostic sensitivity, specificity, positive-predictive value (PPV), and negative-predictive value (NPV) were assessed using 95% confidence intervals (CI). Receiver operating characteristic curves and decision curve analyses were employed to analyze the diagnostic efficiency of these two modes.

RESULTS

Of 126 eligible patients, 73 cases were diagnosed with malignant pleural disease. A total of 1292 biopsy specimens from 492 pleural sites were examined for pathological changes. The diagnostic sensitivity, PPV, and NPV of AFI were 99.7%, 58.2%, and 99.2%, respectively. AFI was significantly superior to WLT, which had a sensitivity of 79.7%, PPV of 50.7%, and NPV of 62.8%. Subgroup analysis showed that the AFI type III pattern was significantly more specific for pleural malignant disease than that of WLT.

CONCLUSIONS

AFI could further improve the diagnostic efficacy of MT by providing better visualization, convenience, and safety.

Medical thoracoscopy in the diagnosis of pleural disease: a guide for the clinician

INTRODUCTION

Developing a feasible and accurate means of evaluating pleural pathology has been an ongoing effort for over 150 years. Pleural fluid cellular and biomarker analyses are simple ways of characterizing and uncovering pathologic entities of pleural disease. However, obtaining samples of pleural tissue has become increasingly important. In cases of suspected malignancy and certain infections histopathology, culture, and molecular testing are necessary to profile diseases more effectively. The pleura is sampled via several techniques including blind transthoracic biopsy, image-guided biopsy, and surgical thoracotomy. Given the heterogeneity of pleural disease, low diagnostic yields, or invasiveness no procedural gold standard has been established in pleural diagnostics.

AREAS COVERED

Herein, we provide a review of the literature on medical thoracoscopy (MT), its development, technical approach, indications, risks, current and future role in the evaluation of thoracic disease. Pubmed was searched for articles published on MT, awake thoracoscopy, and pleuroscopy with a focus on reviewing literature published in the past 5 years.

EXPERT OPINION

As the proficiency and number of interventional pulmonologists continues to grow, MT is ideally positioned to become a front-line diagnostic tool in pleural disease and play an increasingly prominent role in the treatment algorithm of various pleural pathologies.

Delta-Aminolevulinic Acid-Mediated Photodiagnoses in Surgical Oncology: A Historical Review of Clinical Trials

Fluorescence imaging is an emerging clinical technique for real-time intraoperative visualization of tumors and their boundaries. Though multiple fluorescent contrast agents are available in the basic sciences, few fluorescence agents are available for clinical use. Of the clinical fluorophores, delta aminolevulinic acid (5ALA) is unique for generating visible wavelength tumor-specific fluorescence. In 2017, 5ALA was FDA-approved for glioma surgery in the United States. Additionally, clinical studies suggest this agent may have utility in surgical subspecialties outside of neurosurgery. Data from dermatology, OB/GYN, urology, cardiothoracic surgery, and gastrointestinal surgery show 5ALA is helpful for intraoperative visualization of malignant tissues in multiple organ systems. This review summarizes data from English-language 5ALA clinical trials across surgical subspecialties. Imaging systems, routes of administration, dosing, efficacy, and related side effects are reviewed. We found that modified surgical microscopes and endoscopes are the preferred imaging devices. Systemic dosing across surgical specialties range between 5 and 30 mg/kg bodyweight. Multiple studies discussed potential for skin irritation with sun exposure, however this side effect is infrequently reported. Overall, 5ALA has shown high sensitivity for labeling malignant tissues and providing a means to visualize malignant tissue not apparent with standard operative light sources.

Experience Profiling of Fluorescence-Guided Surgery II: Non-Glioma Pathologies

Background

Only sporadic reports of fluorescence-guided surgery (FGS) have been published for non-glioma conditions. In this study, we focus on epidemiological data of fluorescence patterns and report the diverse experiences of FGS in non-gliomas.

Methods

During 8.5 years between July 2010 and January 2019, 900 FGS for brain tumor performed in Seoul National University Hospital. Among them, a total of 73 histologically proven non-glioma patients were analyzed. Indications for FGS have been the possibility of anaplastic tumor in intra-axial tumors in preoperative MRI and an attempt to reproduce known anecdotal experiences of 5-Aminolevulinic Acid (5-ALA) fluorescence.

Results

In cases of brain tumors except for gliomas, the most frequent cases were brain metastasis (23 cases) followed by lymphomas (9 cases) and meningeal tumors (8 cases). And there were embryonal tumors (6 cases), hemangioblastomas (4 cases), and solitary fibrous tumor/hemangiopericytomas (3 cases). Most brain metastases, meningiomas, primary central nervous system lymphomas, and treatment effect cases showed positive fluorescence. Moreover, some non-tumorous conditions also showed positive fluorescence. However, hemangioblastoma and germ cell tumor did not observe any fluorescence at all.

Conclusion

5-ALA induced fluorescence is not limited to glioma but is also evident in non-glioma and non-neoplastic conditions. This 5-ALA-induced fluorescence may be used as an intraoperative tool for various brain conditions.

5-ALA fluorescence of cerebral metastases and its impact for the local-in-brain progression

Aim of the present study was to analyze the oncological impact of 5-ALA fluorescence of cerebral metastases. A retrospective analysis was performed for 84 patients who underwent 5-ALA fluorescence-guided surgery of a cerebral metastasis. Dichotomized fluorescence behavior was correlated to the histopathological subtype and primary site of the metastases, the degree of surgical resection on an early postoperative MRI within 72 hours after surgery, the local in-brain-progression rate and the overall survival. 34/84 metastases (40.5%) showed either strong or faint and 50 metastases (59.5%) no 5-ALA derived fluorescence. Neither the primary site of the cerebral metastases nor their subtype correlated with fluorescence behavior. The dichotomized 5-ALA fluorescence (yes vs. no) had no statistical influence on the degree of surgical resection. Local in-brain progression within or at the border of the resection cavity was observed in 26 patients (30.9%). A significant correlation between 5-ALA fluorescence and local in-brain-progression rate was observed and patients with 5-ALA-negative metastases had a significant higher risk of local recurrence compared to patients with 5-ALA positive metastases. After exclusion of the 20 patients without any form of adjuvant radiation therapy, there was a trend towards a relation of the 5-ALA behavior on the local recurrence rate and the time to local recurrence, although results did not reach significance anymore. Absence of 5-ALA-induced fluorescence may be a risk factor for local in-brain-progression but did not influence the mean overall survival. Therefore, the dichotomized 5-ALA fluorescence pattern might be an indicator for a more aggressive tumor.

Advances in pleural diseases: what is the future for medical thoracoscopy?

PURPOSE OF REVIEW

Medical thoracoscopy provides the physician a window into the pleural space. The procedure allows biopsy of the parietal pleura under direct visualization with good accuracy. In addition, it achieves therapeutic goals of fluid drainage, guided chest tube placement, and pleurodesis.

RECENT FINDINGS

Comparable diagnostic yield is achieved with the flexi-rigid pleuroscope even though pleural biopsies are smaller using the flexible forceps as compared to rigid thoracoscopy. Flexi-rigid pleuroscopy is extremely well tolerated and can be performed safely as an outpatient procedure. Biopsy quality can be further enhanced with accessories that are compatible with the flex-rigid pleuroscope such as the insulated tip knife and cryoprobe.

SUMMARY

With more sensitive tools to image the pleura such as contrast-enhanced computed tomography, MRI, ultrasonography, PET, increased yield with image-guided biopsy as well as advances in cytopathology, what lies in the future for medical thoracoscopy remains to be seen. However, it is the authors' opinion that medical thoracoscopy will evolve with time, complement novel techniques, and continue to play a pivotal role in the evaluation of pleuropulmonary diseases.

Rapid Cancer Fluorescence Imaging Using A γ-Glutamyltranspeptidase-Specific Probe For Primary Lung Cancer

BACKGROUND: We set out to examine the activity of γ-glutamyltranspeptidase (GGT) in lung cancer and the validity of γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) for intraoperative imaging of primary lung cancer. METHODS: GGT activities and mRNA expression levels of GGT1 (one of the GGT subtypes) in five human lung cancer cell lines were examined by fluorescence imaging and quantitative reverse transcription polymerase chain reaction. In vivo imaging of an orthotopic A549 xenograft model in nude mice was performed to confirm its applicability to intraoperative imaging. Furthermore, ex vivo imaging of 73 specimens from lung cancer patients were performed and analyzed to calculate the sensitivity/specificity of gGlu-HMRG for lung cancer diagnosis. RESULTS: GGT activities and mRNA expression levels of GGT1 are diverse depending on cell type; A549, H441, and H460 showed relatively high GGT activities and expression levels, whereas H82 and H226 showed lower values. In the in vivo mouse model study, tiny pleural dissemination and hilar/mediastinal lymph node metastasis (less than 1 mm in diameter) were clearly detected 15 minutes after topical application of gGlu-HMRG. In the ex vivo study of specimens from patients, the sensitivity and specificity of gGlu-HMRG were calculated to be 43.8% (32/73) and 84.9% (62/73), respectively. When limited to female patients, never smokers, and adenocarcinomas, these values were 78.9% (15/19) and 73.7% (14/19), respectively. CONCLUSIONS: Although GGT activity of lung cancer cells vary, gGlu-HMRG can serve as an intraoperative imaging tool to detect small foci of lung cancer when such cells have sufficient GGT activity.

Rapid on-site evaluation with the Hemacolor rapid staining method of medical thoracoscopy biopsy specimens for the management of pleural disease

BACKGROUND AND OBJECTIVE

Medical thoracoscopy (MT) is useful for the management of pleural disease. Rapid on-site evaluation (ROSE) of transbronchial needle aspirates proved to be useful during bronchoscopy. We aimed to evaluate the diagnostic performance of ROSE of MT biopsy specimens and thoracoscopists' impression of the macroscopic appearance and assess the intermodality agreement between ROSE and final histopathologic diagnosis.

METHODS

Sixty two patients with exudative pleural effusions further investigated with MT were enrolled. MT was performed under local anaesthesia and conscious sedation, using the rigid pleuroscope. ROSE with the Hemacolor rapid staining method of the biopsy specimens was performed. Thoracoscopists' impression of the macroscopic appearance was recorded. The final diagnosis was established following histopathological examination.

RESULTS

Thoracoscopic pleural biopsies were diagnosed in 61 patients (98.4%). Group A (n = 25) consisted of patients with malignancy and group B (n = 37) with benign disorders. Area under the curve of ROSE for the diagnosis of malignancy was 0.86 (95% CI: 0.76-0.96, P < 0.001), with a sensitivity of 79.17%, specificity of 94.59%, diagnostic accuracy of 88.5%, positive predictive value of 90.5% and negative predictive value of 87.5%. Intermodality agreement between ROSE and histopathology was good (κ ± SE = 0.615 ± 0.084, P < 0.001). Area under the curve of the thoracoscopists' impression of macroscopic appearance was 0.72 (95% CI: 0.58-0.85, P = 0.001), with a sensitivity of 100%, specificity of 44.7%, positive predictive value of 53.33% and negative predictive value of 100%.

CONCLUSION

Rapid on-site evaluation during MT was found to have high accuracy for predicting malignancy. ROSE can provide the thoracoscopist with an on-site preliminary diagnosis, especially in cases with inconclusive macroscopic appearance.

A pilot study of autofluorescence in the diagnosis of pleural disease

BACKGROUND

Conventional medical thoracoscopy (MT), routinely performed in patients with pleural disease, does not always lead to a conclusive diagnosis. The endoscopic appearance of pleural diseases under white light could be misleading. Autofluorescence has been shown to be an interesting and effective diagnostic tool. The objective of this study was to evaluate the diagnostic value of autofluorescence imaging during MT.

METHODS

Patients with undiagnosed pleural effusion admitted to our clinical center between August 2013 and February 2014 were enrolled. MT was performed first with white light and then by autofluorescence. Endoscopic results of different diseases were recorded, and biopsy specimens were obtained for pathologic analysis. We calculated the diagnostic sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the two methods by comparing them with the pathologic results.

RESULTS

Thirty-seven eligible patients were studied, including 21 with malignancy, nine with tuberculous pleurisy, three with infective pleurisy, and four with no diagnosed condition. Autofluorescence revealed additional malignant lesions, which were missed under white light in five patients. The diagnostic sensitivity and NPV of autofluorescence were 100% (95% CI, 98.5%-100%) and 100% (95% CI, 93.9%-100%), respectively. Autofluorescence was superior to white light, with a sensitivity of 92.8% (95% CI, 89.3%-95.3%) and NPV of 76.8% (95% CI, 67.0%-84.4%). For the specificity and PPV, no significant difference was found.

CONCLUSIONS

The advantage of autofluorescence is its high sensitivity and NPV. It is useful to detect microlesions and delineate the pathologic margins. Autofluorescence can benefit patients with its better visualization.

Autofluorescence thoracoscopy in pleural disease: does it have clinical relevance?

Thoracoscopy has proved to be a reliable tool to demonstrate or exclude pleural malignancy, with a diagnostic yield of at least 90%. (Auto)fluorescence thoracoscopy is a technique used in clinical practice for the early detection of malignant changes in the pleura in order to increase the detection rate of early malignant disease. The sensitivity of autofluorescence thoracoscopy for detecting malignant lesions on the pleural surface was, in our experience, 100% and the specificity was 75%. Autofluorescence thoracoscopy is still in the preclinical research stage and not yet ready for routine use in clinical practice. It will neither increase the (already very high) diagnostic yield of thoracoscopy nor change treatment in patients suffering from malignant pleural disease.

The tumour is not enough or is it? Problems and new concepts in the surgery of cerebral metastases

Cerebral metastases are the most frequent cerebral tumours. Surgery of cerebral metastases plays an indispensible role in a multimodal therapy concept. Conventional white-light, microscopy assisted microsurgical and circumferential stripping of cerebral metastases is neurosurgical standard therapy, but is associated with an extraordinarily high recurrence rate of more than 50% without subsequent whole-brain radiotherapy. Therefore, neurosurgical standard therapy fails to achieve local tumour control in many patients. The present conceptual paper focuses on this issue and discusses the possible causes of the high recurrence rates such as intraoperative dissemination of tumour cells or the lack of sharp delimitation of metastases from the surrounding brain tissue resulting in incomplete resections. Adjuvant whole-brain radiotherapy reduces the risk of local and distant recurrences, but is associated with a well-documented impairment of neurocognitive function. New surgical strategies, such as supramarginal or fluorescence-guided resection, address the possibility of infiltrating tumour parts to achieve more complete resection of cerebral metastases. Supramarginal resection was shown to significantly reduce the risk of a local recurrence and prolongs two-year survival rates. Furthermore, radiosurgery in combination with surgery represents a promising approach.

Pleuroscopy in 2013

Pleuroscopy provides a window to the pleural space while enabling biopsy of the parietal pleura under direct visual guidance for effusions of unknown etiology, guided chest tube placement, and pleurodesis for recurrent pleural effusions or pneumothoraces in selected patients. The procedure enjoyed resurgence when thoracic surgeons introduced the technique for video-assisted thoracic surgery (VATS). VATS is performed under general anesthesia with single-lung ventilation; pleuroscopy is performed in an endoscopy suite using nondisposable rigid or flex-rigid instruments, local anesthesia, and conscious sedation. Pleuroscopy is less invasive; in this review, we discuss the indications, complications, techniques, and recent advances in the procedure.

Current and future options for the diagnosis of malignant pleural effusion

INTRODUCTION

Malignant pleural effusion (MPE) is a frequent problem faced by clinicians, but tumor pleural involvement can be seen without effusion.

AREAS COVERED

Imaging, pleural fluid analysis, biomarkers for MPE, needle pleural biopsy and thoracoscopy. To prepare this review, we performed a search using keywords: 'diagnosis' + 'malignant' + 'pleural' + 'effusion' (all fields) in PubMed, and found 4106 articles overall (until 16 January 2013, 881 in the last 5 years).

EXPERT OPINION

Ultrasound techniques will stay as valuable tools for pleural effusions. Biomarkers in pleural fluid do not currently provide an acceptable yield for MPE. In subjects with past history of asbestos exposure, some serum or plasma markers (soluble mesothelin, fibulin) might help in selecting cases for close follow-up, to detect mesothelioma early. Needle pleural biopsy is justified only if used with image-techniques (ultrasound or CT) guidance, and thoracoscopy is better for both diagnosis and immediate palliative treatment (pleurodesis). Animal models of MPE and 'spheroids' are promising for research involving both pathophysiology and therapy. Considering the possibility of direct pleural delivery of nanotechnology-developed compounds-fit to both diagnosis and therapy purposes ('theranostics')-MPE and mesothelioma in particular are likely to benefit sooner than later from this exciting perspective.

LED light source for fluorescence endoscopy using quantum dots

We present an LED light source for use with standard clinical endoscopes to enable visualization of tissues labeled with quantum dots (QDs). QD-assisted endoscopy may improve the outcome of surgical endoscopic procedures by identifying specific tissue types. QDs offer several advantages over current fluorescent stains due to their high target selectivity, long-lasting fluorescence, large excitation and narrow emission bands, and multiplexing capabilities. The prototype presented is compact, modular in design, and was built at low cost making it competitive with commercially available light sources. The device's efficiency is evaluated by measuring light intensity at discreet locations and by successfully illuminating a chicken tissue sample non-specifically labeled with a 250nM or 500nM QD solution. Ultimately, this device serves as a step towards incorporating QDs into real time, image-guided surgical procedures.

5-aminolevulinic acid (5-ALA)-induced fluorescence in intracerebral metastases: a retrospective study

BACKGROUND

Microsurgical, circumferential stripping of intracerebral metastases often proves to be insufficient to prevent local tumor recurrence.

OBJECTIVE

We were interested in the potential impact of 5-aminolevulinic acid (5-ALA)-induced-fluorescence (5-AIF) as a diagnostic tool for the resection of intracerebral metastases.

METHODS

A retrospective analysis was performed for 52 patients who underwent 5-AIF-guided resection for intracerebral mass lesions that histologically corresponded to metastases from tumors outside the central nervous system. The presence of ALA fluorescence in the tumor was determined in each patient. In 42 patients, fluorescence of the resection cavity after tumor removal was additionally recorded. Data were correlated with neuropathological findings in tissue specimens.

RESULTS

A total of 32 of the 52 metastases (62%) exhibited 5-AIF in tumor parts. All 5-AIF-positive metastases exhibited an inhomogeneous fluorescence pattern. 5-AIF was neither associated with the histological type nor with the site of origin of the metastases. Residual fluorescence of the resection cavity was detected after macroscopically complete white light resection in 24 patients with 5-AIF positive metastases. Residual tumor tissue was histologically confirmed in 6 of 18 patients with available tissue specimens from such 5-AIF positive areas (33%).

CONCLUSIONS

The majority of metastases (62%) were 5-AIF positive, suggesting a potential impact of 5-AIF for improved visualization of metastatic tumor tissue within the brain. However, residual 5-AIF after macroscopically complete resection of a metastasis needs to be interpreted with caution because of the limited specificity for detection of residual tumor tissue.

Fluorescence thoracoscopy in the detection of pleural malignancy

OBJECTIVE

Conventional thoracoscopy, routinely performed in patients with pleural diseases, is not always conclusive in staging of pleural spread. Fluorescence diagnosis (FD) with 5-aminolaevulinic acid (5-ALA) has been used in the diagnostic purpose for various malignancies. The impact of fluorescence thoracoscopy on diagnosis and staging of pleural malignancies was examined.

METHODS

A total of 23 patients with non-conclusive pleural effusions were enrolled in the prospective single-institution trial. Eligible patients were administered 25 mg/kg of 5-ALA ('Alasense', Niopik, Russian Federation) per os 3 h before video-assisted thoracoscopy. After conventional inspection with white light, thorough fluorescence investigation of the visceral and parietal pleura was performed (D-LIGHT Auto Fluorescent System, Karl Storz, Germany). Biopsy specimens of both normal and abnormal sites, as determined from white-light and FD inspection, were obtained for histological examination.

RESULTS

There was no morbidity or mortality due to the procedure. A definitive diagnosis was obtained in all cases: malignant mesothelioma in 13 cases, other malignancies (pleural metastases) in 8 cases and non-specific inflammation in 3 patients. A total of 118 biopsy specimens were available for histological examination. In 20 patients, all pleural deposits (n = 60) detected by white-light thoracoscopy had bright red fluorescence during FD and were proved to be malignant. Upstaging occurred in 12 patients (57.2%) (unsuspected 21 tumour deposits) due to FD examination. Micrometastases of macroscopically normal pleura were detected, only by FD, in one patient. Comparing the results of histological examination of specimens detected by conventional thoracoscopy with that by fluorescence thoracoscopy, we obtained 82 true positive, 10 false-negative, 23 true negative, 3 false-positive results with a specificity of 88.4%, sensitivity of 89.1% and diagnostic accuracy of 88.9%.

CONCLUSIONS

FD using 5-ALA in the pleural cavity is a feasible diagnostic tool when used in addition to white-light thoracoscopy. It improves visualization of additional lesions or even micrometastases in patients with pleural malignancy.

Advances in the diagnosis of pleural disease in lung cancer

Pleural disease in lung cancer can be benign or malignant with the latter carrying a grave prognosis. In this review, we describe and discuss the advances in pleural imaging, procedures, and biomarkers for the diagnosis of pleural diseases in lung cancer. Ultrasound and computed tomography are increasingly applied in the planning of pleural procedures to enhance diagnostic accuracy and safety whilst pleuroscopy gives excellent yield in excess of 93% in the evaluation of cytology negative pleural effusions. Invasion beyond the elastic layer of the visceral pleura upstages lung cancer, and may indicate a need for adjuvant chemotherapy. Biomarkers isolated from pleural fluid or tissue may aid in diagnosis and guide treatment in the future. Magnetic resonance imaging, positron emission tomography, narrow band imaging of the pleura and autofluorescence thoracoscopy are technologies that require further evaluation to better define their respective roles in the diagnostic algorithms of pleural diseases in lung cancer.

Update on pleural diseases--2007

BACKGROUND

New information is available on pleural diseases. The authors selected articles to make recommendations on diagnostic and treatment aspects of pleural diseases.

MATERIALS AND METHODS

Eleven articles published in the English language between 2004 and 2007 were chosen. The basis of selection of the articles was the impact on daily practice, change in prior thinking of a disease process or specific treatment modality, as well as proper design and execution of the study. 5-Amino-laevulinic acid with fluorescent light combined with white light may allow further diagnostic yield in undiagnosed pleural disease. FDG-PET may allow prognostication of patients with pleural tumors. Utilizing ultrasound by trained Emergency Department physicians is a rapid and effective technique to evaluate non-traumatic pleural effusions in symptomatic patients. Serum osteopontin levels may distinguish patients exposed to asbestos with benign disease from those with pleural mesothelioma. Administration of streptokinase in patients with empyema does not need for surgical drainage, length of hospital stay, or mortality as compared to conventional treatment with chest tube drainage and intravenous antibiotics. Silver nitrate may be an alternative agent to talc for producing pleurodesis. Routine use of graded talc (50% particles greater than 25 microns) is recommended to reduce the morbidity associated with talc pleurodesis. Study design does not permit us to conclude that aspiration of spontaneous pneumothorax is as effective as chest tube drainage. Pleural catheter may prove to be an important palliative modality in treating debilitated patients or patients with trapped lung who show symptomatic improvement with drainage; however, at the present time, these catheters cannot be considered a first line treatment option for patients with malignant pleural effusion. One of the studies reviewed showed no significant difference in tract metastasis in patients with malignant mesothelioma undergoing an invasive pleural procedure with or without irradiation to the procedure site. However, the design of the trial does not allow us to make this conclusion at the present time.

Narrow band imaging (NBI) during medical thoracoscopy: first impressions

Background

This is the first ever evaluation of narrow band imaging (NBI), an innovative endoscopic imaging procedure, for the visualisation of pleural processes.

Methods

The pleural cavity was examined in 26 patients with pleural effusions using both white light and narrow band imaging during thoracoscopy under local anaesthesia.

Results

In the great majority of the patients narrow band imaging depicted the blood vessels more clearly than white light, but failed to reveal any differences in number, shape or size. Only in a single case with pleura thickened by chronic inflammation and metastatic spread of lung cancer did narrow band imaging show vessels that were not detectable under white light.

Conclusion

It is not yet possible to assess to what extent the evidence provided by NBI is superior to that achieved with white light. Further studies are required, particularly in the early stages of pleural processes.

Diagnosis and management of malignant pleural effusions

Malignant pleural effusions (MPEs) complicate the clinical course of patients with a broad array of malignancies, which are most often due to lymphomas or carcinomas of the breast, lung, gastrointestinal tract or ovaries. Patients may present with a MPE as the initial manifestation of a cancer or develop an effusion during the advanced phases of a known malignancy. In either circumstance, the median survival after presentation with a MPE is 4 months. Effusions may result from direct pleural invasion (MPE) or indirect effects (paraneoplastic effusions), such as impairment of fluid efflux from the pleural space by lymphatic obstruction or pleural effects of cancer radiation or drug therapy. Because only 50% of patients with cancer who develop a pleural effusion during their clinical course have a MPE, careful evaluation of the effusion to establish its aetiology is required to direct therapy. Management is palliative with interventions directed towards decreasing the volume of intrapleural fluid and the severity of associated symptoms.

Recent advances in the diagnosis and management of malignant pleural effusions

Malignant pleural effusions (MPEs) are an important complication for patients with intrathoracic and extrathoracic malignancies. Median survival after diagnosis of an MPE is 4 months. Patients can present with an MPE as a complication of far-advanced cancer or as the initial manifestation of an underlying malignancy. Common cancer types causing MPEs include lymphomas, mesotheliomas, and carcinomas of the breast, lung, gastrointestinal tract, and ovaries. However, almost all tumor types have been reported to cause MPEs. New imaging modalities assist the evaluation of patients with a suspected MPE; however, positive cytologic or tissue confirmation of malignant cells is necessary to establish a diagnosis. Even in the presence of known malignancy, up to 50% of pleural effusions are benign, underscoring the importance of a firm diagnosis to guide therapy. Rapidly evolving interventional and histopathologic techniques have improved the diagnostic yield of standard cytology and biopsy. Management of an MPE remains palliative; it is critical that the appropriate management approach is chosen on the basis of available expertise and the patient's clinical status. This review summarizes the pathogenesis, diagnosis, and management of MPE. Studies in the English language were identified by searching the MEDLINE database (1980-2007) using the search terms pleura, pleural, malignant, pleurodesis, and thoracoscopy.

Photodynamic therapy for lung cancers based on novel photodynamic diagnosis using talaporfin sodium (NPe6) and autofluorescence bronchoscopy

BACKGROUND

We had previously developed the possibility of use of a photodynamic diagnosis (PDD) system using a tumor-selective photosensitizer and laser irradiation for the early detection and photodynamic therapy (PDT) for centrally located early lung cancers. Recently, we established the autofluorescence diagnosis system integrated into a videoendoscope (SAFE-3000) as a very useful technique for the early diagnosis of lung cancer.

PATIENTS AND METHODS

Twenty-nine patients (38 lesions) with centrally located early lung cancer received PDD and PDT using the second-generation photosensitizer, talaporfin sodium (NPe6). Just before the PDT, we defined the tumor margin accurately using the novel PDD system SAFE-3000 with NPe6 and a diode laser (408nm).

RESULTS

Red fluorescence emitted from the tumor by excitation of the photosensitizer by the diode laser (408nm) from SAFE-3000 allowed accurate determination of the tumor margin just before the PDT. The complete remission (CR) rate following NPe6-PDT in the cases with early lung cancer was 92.1% (35/38 lesions). We also confirmed the loss of red fluorescence from the tumors immediately after the PDT using SAFE-3000. We confirmed that all the NPe6 in the tumor had been excited and photobleached by the laser irradiation (664nm) and that no additional laser irradiation was needed for curative treatment.

CONCLUSIONS

This novel PDD system using SAFE-3000 and NPe6 improved the quality and efficacy of PDT and avoided misjudgement of the dose of the photosensitizer or laser irradiation in PDT. PDT using NPe6 will become a standard option of treatments for centrally located early lung cancer.

Response to ALA-based PDT in an immortalised normal breast cell line and its counterpart transformed with the Ras oncogene

Aminolevulinic acid (ALA)-based photodynamic therapy (PDT) has been successfully employed in the treatment of certain tumours. Porphyrins endogenously generated from ALA induce tumour regression after illumination with light of an appropriate wavelength. The aim of this work was to compare porphyrin production from ALA and sensitivity to photodynamic treatment in a tumour/normal cell line pair. We employed the HB4a cell line from normal mammary luminal epithelium and its counterpart transfected with the oncogen H-Ras (VAL/12 Ras). After 3 h of exposure to ALA, HB4a-Ras cells produce a maximum of 150 ng porphyrins per 10(5) cells whereas HB4a produce 95 ng porphyrins per 10(5) cells. In addition, HB4a-Ras cells show a plateau of porphyrin synthesis at 1 mM whereas HB4a porphyrins peak at the same concentration, and then decrease quickly. This higher porphyrin synthesis in the tumorigenic cell line does not lead to a higher response to the photodynamic treatment upon illumination. Lethal doses 50, LD(50), determined by MTT assay were 0.015 J cm(-2) and 0.039 J cm(-2) for HB4a and HB4a-Ras respectively after 3 h exposure to 1 mM ALA. The conclusion of this work is that a tumour cell line obtained by transfection of the Ras oncogene, although producing higher porphyrin synthesis from ALA, is more resistant to ALA-PDT than the parental non-tumour line, however the mechanism is not related to photosensitiser accumulation, but very likely to cell survival responses.